Cryptology ePrint Archive: BibTeX Citation of Report 2015/556

@misc{cryptoeprint:2015:556,
    author = {Sujoy Sinha Roy and Kimmo Järvinen and Ingrid Verbauwhede},
    title = {Lightweight Coprocessor for Koblitz Curves: 283-bit ECC Including Scalar Conversion with only 4300 Gates},
    howpublished = {Cryptology ePrint Archive, Report 2015/556},
    year = {2015},
    note = {\url{http://eprint.iacr.org/}},
}

You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.